Variable stroke multipiston pump



Jan. 20, 1953 R. E. ANDERSON 2,625,887

VARIABLE STROKE MULTIPISTON-PUMP Filed Dec. 24, 1948 2 SHEETSSHEET 1 30 @452 an W RICHARD e. ANDERSON 34 attorney Jan. 20, 1953 R. E. ANDERSON 2,625,887

VARIABLE STROKE MULTIPISTON PUMP Filed Dec. 24, 1948 2 SHEETSSHEET 2 FIG 5 4 21\% 22: i 2 l I 44 I2 I 62 259 46 42 57 6! f 54 5e FIG-4 RICHARD E. ANDERSON 53 I 3nventor Gttorneg;

Patented Jan. 20,. 1953 VARIABLE STROKE MULTIPISTON PUMP Richard E. Anderson, Portland, reg., assignor, by mesne assignments, to Frank H. Reeves,

Portland, Oreg.

Application December 24, 1948, Serial No. 67,099

My present invention relates to the general art of pump construction of the type used in the 4. Claims. 01. 103-162) dividual cylinders within usual machine tolerances.

pumping of liquids and more particularly to a I variable stroke multi-piston pump. Y My pump is of the type that is adapted'to be driven by power applied on the longitudinal axis of the pump rotor, and to have disposed in parallel relationship and concentric with the axis of rotation, a plurality of reciprocating pistons. The pistons are ported and revolve with 'a central rotor. This rotor is mounted preferably within a sleeve, which is ported to provide the control or" flow desired in the pump. The reciprocation of the various pistons is achieved by placing in spaced axial relationship, at one end of the rotor,

a bearing plate that may be angularly adjusted. This plate, in the neutral position of the pump,

, is disposed at right angles to the longitudinal axis of the rotor, and by tipping this bearing plate in one direction or the other, the length of stroke of the pistons can be varied from nothing, to the extrem travel the mechanism permits of, and the direction in which the plate is tipped will determine the direction of flow of the liquid through the pump.

In my improved design, I believe I have overcome many of the dificulties experienced where pumps, which control other mechanisms, are required to provide liquid under high pressures and which, in order to provide adequate control of the operated mechanism, must be capable of very minute variations of now, and wherein it is also desirable to have a reversal of that flow.

The principal object of my invention therefore,

is to provide a multi-piston pump, which will give i a uniform non-pulsating flow against high pressures.

A further object of my invention is to provide means whereby the amount of liquid delivered by my pump can be adjusted from zero to the full capacity of the mechanism, and wherein the adjusting means that effects the change of stroke, may be set at any intermediate position between maximum and zero without any special locking means.

A further object of my invention is to provide a piston pump in which an immediate reversal of flow through th pump can be achieved without the necessity of unlocking any previously adjusted element.

A further object of my invention is to provide a pump adaptable to high pressures in which the wearing parts are of very simple structure so that they can be very easily and cheaply replaced.

A further object of my present invention is the provision'of enclosingmean s for my pump mechanism. whereby any leakage past the pistons, is immediately put back into the system, and,

' thus it is possible to come up to high pressure with pistons-which are machined to fit their in* A further object 'of my invention is to provide a high pressure non-pulsating liquid pump in which the machine tolerances throughout, can be kept to such limits that the manufacture-o1 the pump can be achieved in ordinary machine tools,

to the end that the manufacturing costs of the same can be kept to a minimum.

Further objects, advantages and capabilities will be apparent from the description and disclosure in the drawings, or may be comprehended or are inherent in the device.

In the drawings: Figure l is an elevation of my pump showing the outer appearance of the same and having certain parts broken away to better illustrate the structure.

, Figure 2 is a perspective view showing the adjustable bearing plate and the linking used in effecting its adjustment and support.

Figure 3 is a cross-sectional view taken along the line 33 of Figure 1.

Figure 4 is an elevational View showing the rotor assembly and the backing or adjusting plate with its supporting mechanism.

Figure 5 is a perspective view showing the drive end closure for the housing.

Figure 6 is a typical longitudinal sectional view taken substantially through the center of my pump with certain parts broken away.

Referring more particularly to the disclosure in the drawings, the numeral Ill designates the rotor element of my pump. This is cylindrical in form and is bored to accept a plurality of step-pistons l2. These pistons are disposed in a circle around the longitudinal axis of 'rotor I0 and parallel to it. This arrangement makes it possible to employ a large number of pistons ii. in a small unit. It

will be noted, by reference to Figure 3, that the form shown throughout the drawings employs I eight of these pistons.

However, it can readily be understood that the actual number employed is just a matter of design. It is, however, desirable to employ quite a number of the pistons in order that there will not occur any surges or intermittent high pressure peaks in the discharged form flow.

Rotor I0 is preferably driven by a coaxially disposed driving shaft M, which may be provided with the usual key member at It, to which any suitable source of rotary power means may be employed. At its upper end, as viewed in the various figures of the drawings, rotor H]. is

provided with a port l8 for each of the pistons it employes. This porting is further illustrated in Figures-:3 and 6. It is tobe; noted that each of thepistons i2 is provided with, an enlarged guiding portion 20 and a reduced diameter working piston portion 2|.

In reference to Figure 6, it, is to, be noted that the enlarged cylinders which accommodate the guiding portions 20 of pistons; l.2- areall'conneets ed by weeping ports, as 22,, to acentral chamber- 24. This chamber provides a catch basin for all leakage past the working piston portions 22, sov

is continuously; revolving within it. It alSo'provides a. relatively" inexpensive way of providing the sealing portions 383 and 3|, whichprovide separators between the intake. and discharge pipe connections; 33 and 34. The material, as

will be noted in Figure 3, of liner 28 is cut out.

in elongated ports between the sealing portion 30. and 3| so that all the various piston ports can communicate with it. In viewing Figure 3, it must be remembered that the piping to bosses 33 and 34 might be either suction or dischargein accordance with the setting of the piston plate.

The power end of housing 21 is provided with a' bolted-on cap 35. This cap provides a bearing for the power shaft I4,, and threaded at its outer end so that by useof a packing gland member, as 36, the shaftcan be sealed against movement of fluid along it. It is noted that a liquid collecting groove, or ring 38, is provided which is concentrically formed in the abutting face of cap 35, and a plurality of discharge grooves or ducts or openings 40, conduct to the outside of the housing unit, any fluid that may have passed by the end-of rotor: l 0..

Disposed below rotor, and the plurality of pistons 12, is abearing'or piston plate 42. This plate ishardened on its upper surface to provide a working surface for: engaging the end of pistons I2. These ends, as will be noted in Figures 4 and 6, are pointed. In the drawings I have shown plate 42 as being. machined toprovide a reduced diameter portion 44, whichin turnis, seated within the carrier 46; The exact manner of. o n ing plate shouldbe varied in accordance with the specificload requirements on. the; unit, It

will be clear, it is believed, that'it; will be relatively simple to mount the same; on. nonfriction bearings if that should be. desirable.v

Inasmuch as the plane surface 48 of plate 42 is angularly positioned in order to vary the-length of piston stroke, and, also the direction of, flow through the pump, it is necessary that it be suitably supported to achieve the various positions that it must. assume to accomplish these purposes. I have found the arrangement shown in Figure 2-, to be very satisfactory, in which a supporting shaft 50 isrevolvably positioned in bearings as 52 formed within housing 21, and to shaft 50 are secured, preferably two crank units as 53-.and 54'. These are fixedly secured to shaft 50 and similarly aligned, each provide two bearing pins as 56 and 51, towhichare attached carrier supporting; links 58 and 59, there being one set of these links on each side of carrier 46. In order. to get the proper holding or positioning of carrier 46, it is necessary to bring the bearing lugs 60 up above the surface 48. It has been found that with the, link, engagingpins 62, so disposed that their axes are'level with, or, above the plane of surface 48, it assists greatly in the holding capacity which permits plate 42 to be p ositioned, but, need not be locked in that position. finother characteristic that I have found necessary inthis arrangement, is to have the center-to-center distances of pins 53 and 51, less than'the; center-to-center distance of pins 62. This action, when this relationship is maintained, is shown in Figures 4 and 6. It is to be noted in Figures 4 and 6, that the two extreme positions of plate 42; are shown. The intermediate position, with,p1ate,42 at, rightangle to axis-of rotor. l0. lathe neutral; point.

Method 07 Operation In use. a suitable source-of power is engaged to power shaft [6. This driving; shaft [6 also drives atv the, same speed, the rotor Ill. Itit is assumed that the surface 48 of plate 42, is at right angles to the axis of rotor It, then there will beno reciprocating movement given to pistons I2, This is the neutral position where no movement of liquid occurs. When the shaft 50 is revolved in either direction, however, it produces an angular displacement of surface 48', which may be assumed to be that shown in Figure 6. Under such conditions, the axis of shaft 50, being parallel to the axis of the two intake and exhaust ports, as 33 and 34, then all the pistons to the left, as viewed in Figure 6, will be pumping fluid in one direction through the tubing connected to bosses 33 and 34. 'Ihisaction is a multiple successive action in which the greatest displacement is reached when the pistons reach the position furthest to the left from the vertical plane, including shaft 50 and bosses 33 and 34. In accordance with, the direction of rotation then we have pistons ascending and descending in equal amounts, so that a continuous flow is provided without pulsation.

If it is desired to change the direction of flow, then plate 42 is. changed in its position, to that shown, inits extreme position, in Figure 4. Here we, have a reversal of the action of Figure 6, so that the pumped liquid will flow in a reversed direction. through openings 33 and 34. It has been foundthat, due to the distribution of pressure throughout the surface 48, and duev to the particular arrangement of links 58 and.,59., that shaft 5.0 will, normally stay in any position it is moved to. Sometimes it, is desirable to havea little friction on thecontrol means,

but, this is merelyrequired to overcome the movement aided by gravity which can occur under conditions of vibration and the like. Otherwise the controls remain in the position set., In the arrangement shown, it is presumed there is some head of liquid at all times above openings 33 and 34, so that the pistons are not required to create suction.

This pump has been found to be ideally employed in the control of any equipment that requires fluid under relatively high pressures. Pumps of this order can easily produce up to 4,000 pounds pressure per square inch if required, and are particularly useful in handling the blades, for instance, on bull-dozers, and other dirt handling. equipment, for setting the. brakes on hoists, wenches and the like, and many other uses. where. it is desirable to have the capacity of providing liquid under relatively high pressures, but which may need very minute adjustment, or which may need a reversal of a flow of fluid. These functions are well within the capacity of this equipment.

It is believed that it will be clearly apparent from the above description and the disclosure in the drawings that the invention comprehends a novel construction of variable stroke multi-piston pump.

Having thus disclosed the invention, I claim:

1. A reversible, multi-piston pressure pump for liquids, comprising: a power driven rotor; a plurality of pistons reciprocally mounted parallel to the axis of the rotor and in a circle concentric with said axis; each of said pistons having a working piston portion and a guiding portion of increased diameter terminating in a central bearing point; a bearing plate adapted to engage said bearing points of said pistons; adjustable supporting means for said plate having a supporting shaft therefor; two crank units secured to said shaft, having pin openings, and pins in said openings, equidistant on opposite sides of the shaft and with corresponding openings in each crank unit axially aligned; pin securing bosses on each end of said bearing plate and pins positioned in said bosses with the axes of the pins spaced from the working surface of said bearing plate in the direction of said pistons and spaced apart a greater distance than the pins carried by said crank units; pairs of links connecting the crank unit pins and the pins of said bosses; said supporting means being adapted to tilt said bearing plate transversely of said shaft and means forming inlet and outlet passageways communicating, on opposite sides, with that portion of said rotor in which the working portions of said pistons travel.

2. A multi-piston pressure pump for liquids, comprising: a housing; a power driven rotor rotatably mounted in said housing having a plurality of piston chambers; a plurality of pistons reciprocally mounted in said chambers in said rotor, parallel to the axis of the rotor and in a circle concentric with said axis, said pistons each having one end exposed outside said rotor; said housing having means forming inlet and outlet passageways communicating, on opposite sides, with the surface of said rotor; and said rotor having passageways connecting said piston chambers with said surface of said rotor; a bearing plate adapted to engage said exposed ends of said pistons; a supporting shaft mounted in said housing, the axis of said shaft being perpendicular to and intersecting the axis of rotation of said rotor; and a plurality of links pivotally connected to said supporting shaft at points spaced from the axis of rotation of said supporting shaft and pivotally connected to said bearing plate at points spaced from the center of said bearing plate permitting tilting of said bearing plate relative to said pistons while maintaining contact between said bearing plate and said pistons.

3. A reversible, multi-piston pressure pump for liquids, comprising: a housing; a power driven rotor rotatably mounted in said housing, said rotor having a plurality of piston chambers; a plurality of pistons reciprocally mounted in said piston chambers parallel to the axis of the rotor and in a circle concentric with said axis; said rotor having radially-disposed, broad openings leading from the outer surface of said rotor to each piston chamber; said housing having inlet and outlet passageways on opposite sides in said housing communicating with said rotor in the area of said radially-disposed openings; each of said pistons having a working piston portion and a guiding piston portion of increased diameter terminating in a central bearing point; said rotor having weeping ports leading inward from said piston chambers, in the path of travel common to said working piston portion and said guiding piston portion and terminating in a central collecting chamber; bearing plate means adapted to engage said bearing points of said pistons; a supporting shaft rotatably mounted in said housing; two crank units secured to said shaft, having pins equidistant on opposite sides of the shaft and with the center of corresponding pins in each crank unit axially aligned; pins on each end of said bearing plate means spaced apart a greater distance than the pins of said crank units; pairs of links connecting the crank unit pins and the pins of the bearing plate means, whereby said bearing plate means may be tilted relative to said pistons while maintaining contact between said bearing plate means and said pistons.

l. A multi-piston pressure pump for liquids, comprising: a housing; a power driven rotor rotatably mounted in said housing, said rotor having a plurality of piston chambers, each chamber having two cylindrical portions of unequal diameters; a plurality of pistons reciprocally mounted in said piston chambers parallel to the axis of rotation of the rotor and in a circle concentric with said axis; said rotor having radially-disposed openings leading from the outer surface of said rotor to each piston chamber; said housing having inlet and outlet passageways on opposite sides in said housing communicating with said rotor in the area of said radially-disposed openings; each of said pistons having a working piston portion and a guiding piston portion of increased diameter, the ends of said guiding piston portions being exposed outside said rotor; said rotor having radiallydisposed weeping ports leading inward from each piston chamber, in the path of travel common to said working piston portion and said guiding piston portion, and terminating in a central collecting chamber; said rotor having an axial opening leading to said central collecting chamber; a removable plug positioned in said axial opening; a bearing plate adapted to engage said exposed ends of said pistons; and supporting means connected to said housing and said bearing plate adapted to tilt said bearing plate relative to said pistons while maintaining contact between said bearing plate and said pistons.

RICHARD E. ANDERSON.

REFERENCES CITED The following references are of record in the file of this patent: 

